This invention relates to a seat belt anchorage and particularly to one that is fixed to a movable occupant seat of a passenger car motor vehicle.
Occupant impact protection systems are presently required on all passenger motor vehicles. Such systems most frequently take the form of an active or passive seat belt assembly which restrains the occupant. The seat belt webbing is anchored to the floor pan of the vehicle along one or both of the lateral sides of the occupant seats. These anchorages must pass stringent strength requirements to ensure that they will adequately restrain the occupant during vehicle impact conditions.
Typical seat belt anchorages are directly mounted to the vehicle floor pan and have straps or extensions which position a seat belt buckle, latching plate or guide loop near the occupant for convenient access. Since the anchorages are mounted to the floor pan, when the occupant adjusts the seat in a fore-and-aft direction with the seat belt fastened, the belts tighten or loosen, depending on the direction of adjustment. This tightening or loosening behavior is inconvenient to the user since it requires readjustment of the belt.
In order to avoid the previously mentioned problems associated with floor mounted anchorage designs, it is desirable to mount a seat belt anchorage directly to the motor vehicle seat so that it moves with the seat during fore-and-aft adjustment. Due to the previously mentioned anchorage strength requirements, however, such a configuration imposes significant structural requirements for the seat adjustment mechanism and associated structure. Accordingly, there is a need to provide an improved seat belt anchorage system in which the anchorage moves with the seat while providing the necessary structural characteristics in an efficient manner.
The above mentioned desirable seat belt anchorage features are achieved by this invention. According to this invention, a belt anchorage assembly is provided which is attached to and movable with the sliding rail of the seat adjustment mechanism. A stationary toothed track fits within the rail and has teeth which mesh with a rotating pinion gear which provides seat position adjustment. The anchorage assembly includes an engagement shaft which directly engages the track teeth when a sufficient force is exerted on the anchorage plate to deform elements attaching the plate to the sliding rail. The engagement system according to this invention is capable of restraining high seat belt loads even though the anchorage is movable with the seat. The mechanism in accordance with this invention further provides the additional benefit of providing a visible "tell-tale" which enables investigators to easily determine whether or not the restraint system was deployed during a vehicle impact situation.
Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings.